The present invention relates to an electrical supply line for operating an electric motor, and to an electrical supply system with an electrical supply line for operating an electric motor. The present invention also relates to a method for operating an electric drive.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Two electric motors, which are driven by way of an inverter respectively, are typically operated in electric vehicles. The two inverters are powered by way of a shared connection network from a shared voltage source. In conjunction with inductances in the connection network and capacitances of the inverters on the input side, an increased tendency to unwanted high-frequency oscillations is observed in the connection network, namely in particular when an operating electric motor is connected to each of the two inverters.
The tendency to oscillate was previously suppressed by the choice of electrolytic capacitors as inverter capacitance. The higher internal resistance of electrolyte capacitors suppresses oscillations. It is also known to attenuate high frequencies by means of ferrite rings. However the internal resistance of electrolyte capacitors and the oscillation-attenuating effect of the ferrite rings results in a conversion of electric energy into thermal energy, in other words into unwanted electrical losses and unwanted thermal stress on the components.
It would therefore be desirable and advantageous to obviate prior art shortcomings and to provide improved and more effective suppression of oscillations without increasing electrical losses.